How the cost of lighting has changed over time

reading by candlelight
Public Domain Woman Reading by Candlelight (1908). Peter Ilsted (Danish, 1861-1933)

The cost of lighting is dropping faster than we can think of silly ways to waste it.

In 1994, Yale professor William Nordhaus calculated the cost of lighting back to Babylonian times and found that, from the beginning of recorded history right through to the 1850s, light was really, really expensive. Tallow candles were a major expense for the wealthy and the poor just did without. (PDF of study here)

nordhaus list© William Nordhaus/ Do Real-Output and Real-Wage Measures Capture Reality? The History of Lighting Suggests Not

His calculations ended in 1992 with the first compact fluorescent bulbs, which were expensive and not very popular. Nordhaus tells NPR:

You look at the picture of what happened here, it's economic history in a nutshell. From Babylonian times to around 1800, even though there were improvements, as best we can tell, they were very modest. And then around 1800 in the lighting -- you can see it so clearly in lighting -- just an enormous change in the pace of improvement.

In this fabulous table from Our World in Data, you can see again how in the UK, the cost of lighting was pretty stable from the 1500s to the 1800s at an incredible 15,000 pounds per million lumen-hours; then it drops as coal oil lamps take over, and then falls to the floor with the development of the electric lightbulb. The chart looks flat through the 20th century but if you click on it, it's 236 pounds in 1900 and 2.6 pounds in 2000.

Goldman sachs chart on LED lighting© Goldman Sachs via ThinkProgress

Writing in ThinkProgress, Joe Romm notes that LED lighting has been one of the fastest technology shifts in human history, quoting a Goldman Sachs report:

Goldman Sachs projected last month that LED lights “are on track to cut power consumption for lighting… by over 40 percent.” That would provide annual savings of more than $20 billion for consumers and businesses within a decade. And that in turn would reduce U.S. CO2 emissions by some 100 million metric tons a year.

LEDs in the bathroomStanley Jevons goes to the bathroom/ Lloyd Alter/CC BY 2.0

For years I have been writing that the drop in cost of LED lighting and technology would in fact lead to an increase in consumption, as people found more and more uses for them. It was, I thought, Jevons' paradox in action, the theory that suggests that as things become more efficient, we use more of them, say building a bigger house or driving a bigger car as the fuel economy improves.

tim hortons restaurant© Stanley Jevons goes for a coffee at Tim Hortons

Every day there are new ways that LEDs are put to use, all of which consume energy where they never did before. I see it every time I go to a public washroom or a [Canadian coffee chain] Timmy's, where the conventional menu boards have been replaced by a line of huge LED monitors.

But while Jevons' paradox may apply to SUVs, it seems that LEDs are exempt. If Goldman Sachs is right, then the energy savings gained from the switch to LED lighting will more than compensate for the crazy new uses that people are thinking up for them.

Tags: Energy | LEDs | Lighting

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